Project Clean Water - TitleBlue top filler
Clean water through local commitment and action - slogan
filler blue piece
Project Clean Water logo
Project Clean Water home page button
overview button
Planning Efforts button
watersheds button
san juan watershed button
santa margarita watershed button
san luis rey watershed button
carlsbad watershed button
san dieguito watershed button
penasquitos watershed button
san diego watershed button
pueblo watershed button
sweetwater watershed button
otay watershed button
tijuana watershed button
for kids button
Report Illegal Dumping button
search button
Blue filler
San Diego River Watershed
Plan - Projects - Activities - menu bar

Map of San Diego River watershed

Hydrologic Unit 907.11 - 907.43
Hydrologic Areas:
Lower San Diego
San Vincente
El Capitan
Boulder Creek
Major Water Bodies: San Diego River, El Capitan Reservoir,
San Vincente Reservoir, Lake Murray,
Boulder Creek, Santee Lakes
CWA 303(d) List: El Capitan Lake: color, manganese, pH; Famosa Slough and Channel: eutrophic; Forester Creek: fecal coliform (lower 1 mile), dissolved oxygen, pH (upper 3 miles), phosphorus, TDS (lower 1 mile); Murray Reservoir: pH; Pacific Ocean Shoreline (San Diego HU): indicator bacteria; San Diego River (lower): fecal coliform (lower 6 miles), low dissolved oxygen, phosphorus, TDS; San Vicente Reservoir: chloride, color, manganese, pH (high), sulfates
Major Impacts: Surface water quality degradation, habitat degradation and loss, sediment, invasive species, eutrophication, and flooding
Constituents of Concern: Coliform bacteria, TDS, nutrients, petroleum chemicals, toxics, and trash
Sources / Activities: Urban runoff, agricultural runoff, mining operations, sewage spills, and sand mining

With a land area of approximately 440 square miles, the San Diego River watershed is the second largest hydrologic unit (HU) in San Diego County. It also has the highest population (~475,000) of the County’s watersheds and contains portions of the cities of San Diego, El Cajon, La Mesa, Poway, and Santee and several unincorporated jurisdictions. Important hydrologic resources in the watershed include five water storage reservoirs, a large groundwater aquifer, extensive riparian habitat, coastal wetlands, and tidepools. Approximately 58.4% of the San Diego River watershed is currently undeveloped. The majority of this undeveloped land is in the upper, eastern portion of the watershed, while the lower reaches are more highly urbanized with residential (14.9%), freeways and roads (5.5%), and commercial/ industrial (4.2%) land uses predominating.

The five reservoirs in the San Diego River watershed supply water to as many as 760,000 residents in the region. Other areas including the Cleveland National Forest, Mission Trails Regional Park, and the river flood plain near Lakeside represent three important undeveloped areas that host a wide variety of intact habitats and endangered species like the arroyo toad, least bell’s vireo, and the southwestern pond turtle. In addition, Famosa Slough, near the mouth of the San Diego River contains extremely productive wetlands habitat.

The mouth of the river discharges into the Pacific Ocean at the community of Ocean Beach. Beach postings and closures from elevated levels of coliform bacteria more than doubled between 1996 and 1999 due to urban runoff and sewage spills. Discharge from the San Diego River outlet may also influence water quality in other nearby coastal areas including Sunset Cliffs, Pacific Beach, and Mission Beach. The extensive groundwater resources beneath the San Diego River provide a cost effective and reliable water supply to four local water districts and the City of San Diego. Excessive extraction, increasing total dissolved solids, and MTBE contamination now threatens this resource.

There are many beneficial water uses within the San Diego River Watershed as designated in the State Water Resources Control Board's San Diego Region Basin Plan.

Satellite photo of the mouth of the San Diego River.

Project Clean Water home page button

Leadership, cooperation, and education are the most
important tools we have for compelling change.
PCW Webmaster